SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a025a152b6b0e1bd4c1907feec4c7865c61baa3842bd5f70c3c4902dfb5eb1c' 
  AND token = 'MZ5g+qQczR/uvZKLXWNkhZWrA3WoZbPBGl4SmG6KuQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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