SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a7c860dd25e41547433680f9101519485f1d0fbf5636c25c70e12b45fa114f7' 
  AND token = '3JXz4FqHNKaZmTLfGlA5/GSSrH+/t7HA2S9xBw8QBGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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