SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd805ec8bef451403241e2d83a4879cd6cd2ce59203f4fa93841fa63db4116620' 
  AND token = 'Wi7dPbluNm+KprPtOSUwKxh87h52JqbUurSc1X+FdI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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