SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3267fc28e36878bd634378af010d5c14971c85086cf657ad9eebb562f5c43f28' 
  AND token = 'DEoVKW4Ofp3LIHcqN/2YSgf4uFA+oeUhKySkTQLcdIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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