SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc348b90403b9c89168d78535f5a176aa8adcd247160aa28a25207c8cca5adf0' 
  AND token = 'EzBIcptAiNvArFnudbLa8SQKiPTNSjmJ8gtekzh7wCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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