SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9437fe2caf2a0ddd21ec9c8b5a0bee26e2c41fc16d484fc53c0baebbe7a0fc96' 
  AND token = 'H69IAzuqwXFpI00D9bGLNEgYQrrJ5PW+Cxhedlmq+6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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