SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '014521d52683ebc12e8bc3a16d10949e71affb789007d88c22a7c2c90a330897' 
  AND token = 'qWReITvduXwlnjGKYe1sgoBrKLpSHmXY/SEDQYcWeLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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