SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6b296179b32fddc29b94d6d5498a996fb53067005a2cea9fc5e9e27c7c4cffe' 
  AND token = 'ZRmaPvjDdkfjgAsmg/P4qk+GRlRt/cwHXKLV3RsA7Cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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