SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f75086d2608afe626cbf3eaa2ce3a000a981cb401bda75f67f18ea818d9003c5' 
  AND token = 'sF1olzPjTUsxKqi2LX7JIkESKMKcfNposEtQsge4WAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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