SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2cbc526fcc66a2e085ed426bbe3f33539d49d7f985a6c91b12a4bd2e794fc19' 
  AND token = 'YjHyc8re2CZIEABBUUKePdyCHfTJyCsJHDSvgsTlQzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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