SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eae9bfe550669bdc2ead1ebe3fa8dd681547c513a93f47aec3b56bfd974a2983' 
  AND token = 'sQ4hgywlMdcnXuemyh4a8gwAezAGlMAI61j3WkRMwds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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