SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe4bc2973c7ad538d8191a170aba5acffde14af67d0c30ede84edc00a1d7476' 
  AND token = 'DUHwpV5FstrLdQyJKlYyTIGrukvT0ybRwcfEYqidanw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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