SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f1952a51b2f57fd4d4cfea54daae840aa1b2fc8b9b838ef339ced09f45c6e33' 
  AND token = '/27mzRrDpf7A+JPgqXPgB06ewbwrQWsPBhily2xFAH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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