SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2505c9afbcb4a177a3839387d713db661d7ac61042c8b97cb856bff69976700' 
  AND token = '71HXgXvnLuRk8mwyoyGDCnDBDqveBhw4J7JRNOFPvR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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