SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '434ff75c619a2e2096b21f17227e9c4f041b048ca507caa3679113de51c4a9ed' 
  AND token = 'LDwQ1z7/cGQFlBMWPrPTB+vVu1pOHXPNfzwwN6lZRg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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