SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9f9749b823712c6c4dfbedd99fc3a907eecc3fc42649b6b21550e1c19e3fd0b' 
  AND token = 'E3j8+LG7GYJx+SzRh4kUrBsewOZr1ZbCeL1Dz5q4Om8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}