SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76a2844cb91d86e4b077418e48e63c6e666407fcbcb082191b45a88a4f55809' 
  AND token = 'Jr/j1qeL7BO+0C8xfi0kLw49OesOaySh9nyXRnaeZp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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