SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0803456f9aabfcb04ed00589a991e85162b3ae5427bb6b6d202136b5ff509a42' 
  AND token = 'tD1d5dk0GOIL5+KlkYmC3vUMGMGrCQCIAOKQIWuuIiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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