SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b913c06b6aa644fe9b317d9fefd0e4efe4107de6388b1f05f44c3b85d821684a' 
  AND token = 'nN95/lLRmCaIinygTNnXTE1x8slCKbOw2u4i+LBH5DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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