SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b81d7e073d20518b83bded3062515fedf4a71adae4ac7c757a476cf5edb94747' 
  AND token = 'zZdpFCfw358/I0Gcpynqp4Bt6EyBj4eZa/lq4AlLJPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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