SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fb6b85262e9f787d85cac4e6e1c06d3124228f80ab73965847a349e0c060862' 
  AND token = '4K6xREGQfZXAdLKhCUZWkvvKq4Bnv7QLACLX2zEIwBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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