SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a70ecd753e752d17dde233eb93e3e73d5865fdd72e0338ab25514080eaee4582' 
  AND token = 'SVcUVvD66Qt5N2bO/TSqMVCE26a3tgpfRkCdfCI+rMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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