SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '929d74a6d998bdb2ab5871b39710860e8ab231f595a0fcb7543d32aea3be8a49' 
  AND token = 'IGC+WtYojiBfLJZsoqisnBJYWQxZjegd5o6FFmuaJsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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