SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbb42a2dbc4b93154530624595bd5bf5d3f4c2ffe09815fa2850b5037858b32' 
  AND token = 'amDHMGduDRhrSYaZbYM9ZrhAMRlMK/TLQN/cHifTswk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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