SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '407125bd1912cd1ee76015f434ff374667c0dbdef6e90f4b8f5477dc1585afcb' 
  AND token = 'm9BQ4YpuUJD40pLKl02ERHEGrbQcmudcNswS/5uX8Ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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