SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '526372323f02dd6a298aef01b42f10dce063131f561b9e501b2abe92f732ecbf' 
  AND token = 'MjWCywJllXXDctTRxxuehpJ0HdR0SObOnE5ByyxH4ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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