SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7270a6b9d28c599b040d8f30e0e60b4006013f8949917e35dbb844e0bfff2d8f' 
  AND token = 'TVAEgCkZdBFCPgzAxYpNpG2RLOc1xgOcVDsiwn9BaeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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