SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbd7294f82bd98a977a2fa1e46e52188f51fc17b04ae52978b427de0053dc1a1' 
  AND token = 'n1ejnAZexPDs52dUT4LOmYsfdtbAgXqToVqhkDKSWy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00087

JSON explain

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