SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da2c3a1651eeb1fc40bd040b42987f48cce2db023ce06163b3720ebd4905cc18' 
  AND token = 'BMlgIaFlF9SiTw3hylqeEgtrVTPR12P84ZQnxI1z7QI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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