SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275db687a64bd33b17f9b70df8ce940913c2c4cf594307995a1469a784fa0b0f' 
  AND token = '/o4Op2c8hK28CLEzPH1BaLDlZWQOC5CrASTgJv+FKp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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