SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75cfaa5cc8cd3f2bb7ecf31fc5d516300585211079fc62c4bc117f3f2e0b2db2' 
  AND token = 'kRFzOCpZCpvGzw2Zw4POYPj4aJA7wsquvpE+C3s/IpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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