SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '988b64bb9c89e927fce7627791a6fbd7f844d46144045f2939164fab87f51dd8' 
  AND token = 'MkqQUZTR0zBpFoPYDQgVye4GGTS8TSt273JkYcXkpxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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