SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fef3ad99427ad1eb3bd0d573b889946ebe3ee0976f6193b0828acd57987cf37' 
  AND token = 'khp7gNDXDfgNvBU84lPC7CpNwLLwwfqqnvfCJEDCfmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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