SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc74c67a2267a9a46ad318f54b91eb64718de03b69ecf3424d48a586de8b09de' 
  AND token = 'xz5AkPy9gRU/57mP/wG1shICxtL6r1XvkMh2pS7qk+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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