SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b64acb84dd2217667745c63eafb7a403aaaba6ec5a839e35555c58adefa70496' 
  AND token = 'lRhGqOHLLvUVO2tcvL3Y0WLDDcY8u4I835FihJypdT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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