SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab368767abbcb4da8065824fc53a0b44d5b5c795ddc7af237f07865c10763413' 
  AND token = 'DCKSVhbgbufq8QL9kHzlKKjbkmKkGurYfmIhlsYexN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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