SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e91d7e34c1ba4d9bf528acf2a604853f74e3315d97a04b7b41c0fd2e8bbcafb' 
  AND token = 'JlfGGydIRFpviGXCU6uv1z1Jkqef1/zTqxk2W+fgruI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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