SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ff5a40df15e5a50f963a9a83e92b7fed2cdf184e186666cc507670480d142b0' 
  AND token = 'JBSeHhy4RXS54kgqlqQ8cFBLFatnISHaplaQ5wtzPYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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