SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7437e908380f7be650a75fc21296f8087ac0ef42504dfa1905628639ec9f7af6' 
  AND token = 'qtsf7/pL1vY/K6zyLjDR8ebPSW4dHnVaEG4h4mtFD/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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