SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c68cf436ae1421f868008fd2f05ba9a9705155a76135c9f3357507fb5102a89' 
  AND token = 'fzfkEr4V+F+EKPO8S5+lNQoCSxiz4XAf4giOcM080EM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}