SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '380efefca7874607abe428307af133027c1592fd35d85ef3a8ac4084a702f86c' 
  AND token = 'wrRKYFsb9IRr+dHvLOntNrRnTRad9eLyrOCq350QOBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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