SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8248cf6cb74977e85d9691c09e62e1632f34f6e52b35c0e727c1d0d7445d9570' 
  AND token = 'Y35jKSCSpr7ZUAkf4h8vqlsE5MBrapsKfxBCi0gvaYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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