SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f881289c781129ac11cdc0a4184328672ffbdce785a2640cbf706802ac72547d' 
  AND token = 'sZPTRuDFfBJDH40tL0TDMsLHct4Q+R77VxBknPeEFj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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