SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2156cd4c43222339a7cf67153fbd865e1556797d8cc04d50abb27f89ac52925' 
  AND token = 'MgUgqju9ZmOqcDQVfIE+1/VbRxxGGi6qZ1ALOstnP6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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