SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a257322ae93eca79ad4e046e2866ae506fd2cf882289d91683cb2dabcb3a4357' 
  AND token = 'C6UDIAbSOyMcJYGvNUAG0Mva0aYDJkBG1oBM1x/MaCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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