SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cefc2ff1230dae19ce02846b0d81d1d03d97a9c6d6a2e9ad6901eb6fa4d90b69' 
  AND token = 'Ld/vnYlEN/nohFENgilIeUSwmCDMkjPoPL/bC7GYjSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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