SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d76bde2c5e567f3ff9607823b3fd2f51e9fe7f137e44d5469d3d38edcb5f72a' 
  AND token = 'Vu4J9v042JKzamG3xHYT40aZ9diS+XcqgPyw3QPmQUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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