SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a551328dd3c457839976f278ccbd0a16e406a8160031f7e438a8c01c19ef519a' 
  AND token = 'wazWfkFXeQtYZs2LKq1vC3BzevM2rShLhYbcnlvgqoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}