SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b6f163d0a142fefad7bb9a154b40a623e36c8968009742803c81f1339be6c72e' 
  AND token = 'QdfCRbGI9tXPXK/tnMHtP2xZu6Y6wb1LDTkpja/VzHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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