SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7abfc11ecc556d3f717e3a8930826ccda0f740902a6a17b48e3660c5529ff8b' 
  AND token = 'EsLwMx5ClR3QZuXuTiJRYfQPdyBDHUHYEYdsZUomHkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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