SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8cf907ba08f566011444336295802425aa4512f019c50afd711ca549d5a67e61' 
  AND token = 'jc3UO4E8yjLIsVrbL8xulmEwRU4HfzGLYGxVd9DFIkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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