SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e01774f19b2fc0e1136bc69548c9208c1f73b3db542a1d5125f8d857f9069623' 
  AND token = '38fBNTGoj3/kOeGKMUbiAlozFUoQDxsePJVgji8BLzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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