SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79a8534577414f26857482f0900dabd03126252e1e231bf9c9cf6a4840f65cf5' 
  AND token = '9EhQWaTrhfH8cUzVWW1TFIGmax9kgSZfeB7fhTWw0v0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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