SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06dc0bb3551cff80ec28709821f4030180d996ed522483ac437f5d292327d66f' 
  AND token = 'fq4W9RDZGLjNflcLlzcV+QPqLXLjXUm1Gb/Ig6egDGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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