SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37d6090213205f51080160cfc53a1ccc40b66d800c34e32e9371137794f6f154' 
  AND token = '+gS2IXEJlr4kd3UnjgQzzPqnCl3lrJsYEnfU3hl5bhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}