SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06808247340aa5d8b21c54a2d0bb52e48b846bca973492dec1bfd7148aff8bc4' 
  AND token = 'dKy16EFvshSj+BuZqkHdeH3ndTlzxgs2GZIJI0p6+KM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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