SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4557ec5f3f8f554814d22f7654256baa39232692080c1f935736ad60855096ff' 
  AND token = 'KvoTR+qZHYnX5qf83/Min/9XDVgGK6YyJppTndLDKas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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