SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ebb3e73ae5ecd25d0ab95efa14b1247a123503e2844449dd927a90bedfe8465' 
  AND token = 'YbapvHmdGOfDK1hkdtYaZH37lYDMnvEhmI4DKnGVLEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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