SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '055156a778bfac577014c653bb38058f47f262e26305aab2ce97dc53092e8841' 
  AND token = 'vFUiwIUOITbhJlfR1c0ktFRJTFbRdWwJLDSs5pR7o0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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