SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5af209db7657ed75288df731ffa036a0da3e24dbb49f5fd03dd516aef1da9a3a' 
  AND token = 'uu5Hf9WE0Mf/yKGmhDAe05CC+fQwMsspv+UaKypR3lE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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