SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8af065963ee3857c251506fbcbfc0da2b27a77d8d125fb0507f75892cc632f77' 
  AND token = 'UaP1jzDYLGvVwAg7CYiIB4UV3vnf4ZtnTdSf7Wnx4uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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