SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d90dc4c6467a8bf7fd428db1140f28b7b220368dfe3a858bae49607955e2bee' 
  AND token = 'gSSrDh4B7UTo1aImPmhyvAqdkY7bMKIkrbT3tinJ2wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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