SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20d87e59a5b52d09f2b179f1f826dae0e055b3e9fa3398e2c2f08e92d368c769' 
  AND token = 'gbJMURZGkrZIhKMVh7QOOFJPS6p4LDpRRTdeWvJ+rQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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