SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '574748b68f2e45eb97d53ec94b725765c20534ab9b29b5de69f3761af6fee578' 
  AND token = 'FFXfiKB/dCi/bwzvhMG+ef7o69Qlmtzdj9C2JeKE6g4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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