SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731b6d144577ba290b157e3fd08a1dd1b1aa6b069aecf6c237314bccb6d5129b' 
  AND token = 'cDMJuuOv0d4QZWwg1xXIgsKdoej0pMXzeAoEJltCaH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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