SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66e2b40ea6ad4e2a4cd0eaaaa0e90615d362105819f3a670028f2859ba368f44' 
  AND token = 'mIoRxGxwQJXEPfL1WcNQdjLPEabTGlIlvnt7sXpCNtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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