SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2f521c266be23721e13ff657f6000100c68fa8d705ac00d70a80bd78188ec08' 
  AND token = 'hoXw1bgG0wOvCpU9uhdcc40SPPoCtAAARHb8g6pUwmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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