SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd167753b23699252bb516066a7eb4bd15683c9a6954cc426753eb139fd2ad991' 
  AND token = 'iLV40NvPi+JxXK3KGsUxvEs7AralZ9wnCrzGTADGuec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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